The actinides are a series of 15 chemical elements in the periodic table, ranging from atomic number 89 (actinium) to 103 (lawrencium). These elements are known for their radioactive properties and are typically found in nature in trace amounts. They include well-known elements like uranium and plutonium, which are used as fuel in nuclear reactors and in the production of nuclear weapons. Actinides are characterized by their ability to form complex compounds and their tendency to exhibit multiple oxidation states. Most actinides are metals and are usually silvery or gray in appearance. Due to their radioactivity, handling these elements requires special precautions to ensure safety.